1--Field of the Invention
This invention relates to a device for multimode management of a cursor on the screen of a display device associated with a processor.
2--Description of the Prior Art
In a general manner, it is known that for pointing on a screen, two principal pointing modes are currently proposed, i.e. the so-called "relative" pointing mode and the so-called "absolute" pointing mode.
The relative pointing mode, which is operated by mouse or track ball type manipulators, consists in sending to the processor managing the screen, the coordinates of a cursor or pointer, expressed in a Cartesian coordinate system having as origin the position of this cursor or pointer. The displacement of this cursor on the screen is then controlled by a homothetic displacement of the manipulator (e.g. displacement of the mouse on its supporting surface).
This pointing mode has notably the following advantages:
the manipulator can moved blindly, the operator need only watch the screen without any concern as regards the position of the manipulator; PA1 it enables great accuracy to be obtained, as the operator can follow the path of the cursor (possibly in a large-scale screen area) up to the required point.
Conversely, this solution has the drawback of being relatively slow (the time required for the operator to bring the cursor from one place to another may be deemed too long for certain applications).
As for the absolute pointing mode, it uses, at control source level, a sensitive surface (e.g. a touch-sensitive surface) of finite dimensions and of shape having isomorphic (or even homothetic) correspondence with a display zone which may consist in all or part of the screen.
According to this pointing mode, in order to position the cursor at a given point of the screen, the place corresponding to said point need only be indicated on the touch-sensitive surface.
It so happens that this pointing mode, which does not truly enable the operator to work blindly, is faster but does not enable a good degree of accuracy to be achieved easily: more or less lengthy trial and error is frequently required to obtain a precise point. It is for this reason that this mode is most often used for selecting given zones of the screen assigned e.g. to values or functions.
The two above-mentioned pointing modes can therefore be seen to be complementary in that the advantages of one suppress the drawbacks of the other, and vice versa.